Modulation of epidermal growth factor receptors by retinoic acid in ME180 cells.
Retinoic acid (RA) increases epidermal growth factor (EGF) receptors in many cells; in ME180 cells, a human epidermoid carcinoma, RA resulted in a dose- and time-dependent reduction of EGF binding. In RA-treated ME180 cells, binding was 41% of the control. The reduction of EGF binding was due to a decrease in the number of receptors, from 8.7 x 10(4) to 3.6 x 10(4) per cell. The difference was present 8 h after the addition of RA and was reversible 3 days after its removal. Scatchard analysis indicated that RA did not change the binding affinity of EGF (Kd = 1 nM). Also, RA did not alter the rate of EGF internalization or the down-regulation induced by exogenous EGF. Flow-cytometric analysis revealed that RA did not alter the cell cycle. Soluble cell membrane extracts were prepared in a Tris buffer with protease inhibitors, immunoprecipitated, electrophoresed, and immunoblotted with an antiserum to EGF receptors. The EGF receptor band of Mr 170,000 was decreased in RA-treated cells. These results suggest that RA reduces the synthesis of EGF receptors in ME180 cells.
Zheng
Z S
ZS
Department of Dermatology, University of Rochester Medical Center, New York 14642.
Goldsmith
L A
LA
D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D015536:Down-Regulation; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000096:biosynthesis / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006801:Humans; D013997:Time Factors; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000378:metabolism* / Q000473:pathology
D014212:Tretinoin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors